Brief Summary

With its horny frill and prominent brow horns, Triceratops horridusis one of the most recognizable dinosaurs. It lived in the Late Cretaceous (68 to 65 million years ago), up until the mass extinction that killed all non-avian dinosaurs. At 8 m in length and weighing approximately 9000 kg, T. horridus was the largest of the frilled ceratopsians and dwarfed all land animals alive today (1). Fortunately for paleontologists who wish to study this spectacular dinosaur, T. horridus is commonly found in fossil deposits. Paleontologists previously have thought that there were large numbers of Triceratops species as well. Of the many Triceratops species described, today only two are generally recognized: Triceratops horridus and Triceratops prorsus. The other “species” are now understood to be different growth stages or genders of T. horridus or T. prorsus (2).